Environmentally friendly dual lube venturi filter cartridge

ABSTRACT

An environmentally friendly dual lube venturi filter cartridge which has no metallic components. A plastic centertube having a venturi section supports a bypass filter element on standoffs molded into the centertube. An outer concentric full flow filter element surrounds the bypass filter. The full flow filter is supported on a plastic centertube which creates a gap between it and the bypass filter. A first bypass filter endcap both seals the bypass filter and provides standoffs for allowing full flow oil around the bypass filter. The standoffs thus split the full flow which progresses through the primary filter in two paths, a primary path around the bypass filter and into the centertube, and a bypass path through the secondary filter and the venturi. Plastic upper and lower endcaps carry grooves for simple sealing gaskets, a radial seal gasket on the bottom which seals against both the endcap which carries it and a flange in the housing, and an axial seal gasket at the top.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 10/457,110, filed Jun. 9, 2003, now U.S. Pat. No. 7,014,761which application claims the benefit of U.S. Provisional PatentApplication Nos. 60/387,196 and 60/387,235, both filed on Jun. 7,2002,the entire disclosures of which are incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

This invention relates to filters, and more particularly to a dual lubeventuri cartridge filter.

BACKGROUND OF THE INVENTION

Venturi dual flow filters are described and claimed in U.S. Pat. No.6,478,958, assigned to the assignee of the present invention. Thosefilters have the desirable characteristic of filtering all of the oilthrough a primary filter, then filtering a predetermined percentage ofthe oil through a secondary higher density filter. A venturi tube isused to provide a passageway for all of the flow of filtered fluid backto the engine. The majority of flow in the passageway is passed throughthe primary filter only. The size and positioning and characteristics ofthe venturi in the tube, along with the flow rate, determines thepercentage of oil which is brought through the secondary filter and theventuri port to join with the primary flow back to the engine.

Filters of this type, while presenting useful filtering advantages, canpresent a disposal problem. Due to ease of installation, manyapplications prefer the spin-on cartridges disclosed in theaforementioned patent. These have a metal outer case, a metal baseplate,and other metal components within the filter. Even if replaceablecartridges were utilized, they also have significant metal components,often in the form of centertubes or support grids for supporting thefilter element, and metal endcaps for sealing the ends of the filter andmaintaining relative position of the components. Thus, significantelements of filters of this type will not burn, preventing the use ofincineration for relatively complete disposal of the spent filters orfilter cartridges.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, it is a general aim of the present inventionto provide an environmentally friendly filter cartridge, capable ofbeing incinerateable, and capable of functioning as a dual lube venturicartridge filter. The cartridge is environmentally friendly in that itcontains no metallic parts.

In practicing the invention, the cartridge can be made from a limitedclass of materials, preferably all incinerateable. The materials includethe media (normally cellulose or perhaps polyester with plasticbacking), plastic elements such as centertubes and endcaps, rubbergaskets, and potting compound (epoxy, plastisol, hot melt or urethane),all of which are incinerateable. The fact that the cartridge will burnand is lightweight (due to no metal parts) simplifies disposal.

In a particular embodiment, the invention provides an environmentallyfriendly dual lube filter cartridge which contains no metal parts. Anon-metallic venturi centertube has a venturi throat associated with atleast one venturi port. A bypass filter is arranged coaxial with theventuri centertube. Ribs on the venturi centertube support the bypassfilter and create a first flow passage between the bypass filter and theventuri port. A full flow filter having a non-metallic centertube ismounted coaxial with the bypass filter. The full flow centertube has abore which is larger than the outer periphery of the bypass filter so asto create a second flow passage for single filtered fluid. A firstplastic endcap seals a first end of the bypass filter and the associatedend of the venturi centertube. The first endcap has projections forcreating a flow path for single filtered fluid from the second flowpassage to the venturi centertube. A second plastic endcap joins all ofthe components including the liner, the full flow filter, the bypassfilter and the venturi centertube. The second endcap has a centralpassage connected to the venturi centertube for flow of oil from thecartridge. The second endcap also has an annular peripheral groove nearits outer periphery for receiving a skirt-like radial seal gasket. Athird plastic endcap encloses the upper end of the cartridge and issealingly joined to the full flow filter element. The standoffs on thefirst endcap provide a flow passage between the bypass element and thethird endcap. The third endcap has an annular peripheral groove on itsouter periphery for carrying a simple flange-like radial seal gasket.

Other aspects, objectives and advantages of the invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational cross-section showing a dual lube venturifilter cartridge constructed in accordance with the present invention;

FIG. 2 is a cross-sectional view taken along the line 2—2 of FIG. 1;

FIG. 3 is an elevational view showing the cartridge of FIG. 1 in afilter housing;

FIG. 4 is a cross-sectional view showing the venturi centertube of theembodiment of FIG. 1;

FIG. 5 is an elevational cross-section showing a partial assemblyincluding the venturi centertube and the bypass filter with a firstformed endcap;

FIG. 6 is another partial assembly showing the addition of the full flowfilter with centertube and liner, along with a second potted endcap;

FIG. 7 is an elevational cross-section showing the completed cartridgewith the third and final endcap in place; and

FIG. 8 is a plan view of the filter cartridge showing the line 7—7 alongwhich the sectional view of FIG. 7 was taken.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The function of the dual lube venturi cartridge is to provide full flowfiltration of engine lubricating oil and bypass filtration of thelubricating oil, all in one cartridge. The venturi provides a means ofbleeding the oil filtered by both the full flow and bypass filter mediainto one stream, allowing the cartridge housing to function with onlyone inlet and one outlet. The theory behind the operation of a venturicartridge is fully described in the aforementioned U.S. Pat. No.6,478,958, the disclosure of which is incorporated herein by reference.

The cartridge of the present invention, in contrast to that disclosed inthe aforementioned patent, contains no metallic parts and is thusenvironmentally friendly. This makes disposal of the cartridge arelatively simple matter.

Turning then to FIG. 1, there is shown an elevational cross-section of acartridge 20 constructed in accordance with the present invention. Thecartridge includes a full flow filter 21 which is supported by a plasticcentertube 22 and, when desired, covered by an outer perforated liner23. Full flow filter 21 is concentric with a bypass filter 25 which isslipped over and supported on a venturi centertube 26. (See also FIG. 2)The filter elements 21, 25 are preferably pleated paper (cellulose orperhaps polyester with plastic backing). It will be seen that thecentertube 26 has a venturi section or throat 27 including one or moreventuri ports 28 intended to draw flow from the flow passage between theinside of the bypass filter 25 and the outside of the venturi tube 26.The filter elements and associated components are sealed in only threeplastic endcaps, as will be described below.

The housing into which the cartridge is fit is not shown in FIG. 1. Butwith an exemplary housing, to be described below, the housing wouldprovide an inlet of unfiltered oil at 30 which would be distributedaround the exterior periphery of the full flow filter 21. The fluidwould pass through the filter to the flow channel 32 created between theinside of the centertube 22 and the outside of the bypass filter 25. Thefull flow through the primary filter then splits into two paths, a fullflow path and a bypass path. In most applications, the majority of theflow, the primary flow, would be along the arrows 33 to pass betweenflow passages generally indicated at 34 into the center of the venturicentertube. This full flow accelerates through the throat 27 of theventuri to create a differential pressure which will tend to draw oilfrom the flow passage 32 to the flow passage 31 which exists between theinside of the bypass filter and the outside of the venturi tube. Thissmaller predetermined flow, the bypass flow, is indicated by thereference numeral 36. The two flows 33 and 36 will join in the venturitube to create an output flow 37 which is substantially equal to theinlet flow 30. All of the oil in the outlet flow 37 has been filtered bythe primary filter 21, and a predetermined percentage has also beenfiltered by the secondary filter 25.

FIG. 3 shows an exemplary housing into which the filter of FIG. I can befit. It will be seen that in the exemplary housing inlet fluid isprovided through an inlet port 42. In the illustrated filterconstruction, the outer liner 23 is constructed with no perforationsnear the axial center of the filter (see the left side of FIG. 1), wherethe main oil flow impinges on the filter, in order to protect the filterfrom direct oil flow as it enters the cartridge housing. The housing hasan outlet port 44 which is connected by an internal passage 44 a in thehousing to the venturi centertube 26, for receiving the total outputflow from the filter. The housing has a removable cap 45 which isthreaded onto the housing to compress an axial seal gasket 50 set in anannular groove 52 on the periphery of the upper endcap. The lowerportion of the housing has an annular flange 46 against which seats theradial seal gasket 54 which is fit in an annular groove 55 formed in thelower endcap 56. If desired, a handle 58 can be formed in the upperendcap to assist in removing the filter from the housing. The housingcan have other ports and apparatuses associate therewith, none of whichare important to an understanding of the cartridge of the presentinvention, to which attention will now be returned.

The construction of the dual lube venturi filter cartridge starts withpre-assembling certain subassemblies. A first is the bypass elementsubassembly which is based on the venturi centertube 26 shown in FIG. 4.The centertube 26 is preferably molded plastic. As previously describedit has a restricted venturi throat 27 having a plurality of venturiports 28 formed in the throat area. Conveniently, the tube 26 includes aplurality of raised ribs 60 which, as will be seen below, tends tosupport the inside of the bypass filter while creating theaforementioned flow passage 31 (see FIG. 2) between the outside of thecentertube 26 and the inner bore of the bypass filter 25. Theprotrusions 61 in the area of the venturi throat are preferably largerthan those at the ends of the venturi tube so as to present a relativelyconstant circumference for receipt of and support of the bypass filter.As a further convenience in supporting the bypass filter and aiding themolding of the ends of the centertube into respective endcaps, thecentertube 26 terminates in a pair of end flanges 64, 65. Preferably theouter circumference of the flanges 64, 65 is about the same as the outercircumference of the ribs 60, 61.

To form the bypass subassembly, a bypass filter element 25, preferablypleated paper, is fit-over the centertube 26 as shown in FIG. 5, andboth are fit into a channel 70 a in a first endcap 70. Potting compound,such as epoxy, plastisol, hot melt or urethane is introduced into theendcap to seal the pleat ends and the end of the centertube to theendcap. The endcap 70 not only performs its traditional endcap function,but also provides standoffs 72 which tend to form the aforementionedpassages 34 for full flow oil to pass around the bypass filter and intothe venturi centertube 26.

A second subassembly which is conveniently produced is the one includingthe primary filter 21 supported on a plastic centertube 22 and coveredby an overwrap 23. FIG. 6 shows that subassembly positioned over thebypass subassembly to form a dual concentric filter arrangement. Thecentertube 22 is of sufficient diameter to create the fluid passageway32 between the primary and secondary subassemblies. As noted above, thepassageway provides for the passage of oil upwardly through the filterand through the passages 34 created by the standoffs 72 of the secondaryfilter endcap 70. All of the subassembled elements are held together bya second endcap 74 which joins the primary filter subassembly and thesecondary filter subassembly. A seal is provided by introduction ofpotting material as described above. The ends of both filter media packs21, 25 are sealed and potted into the endcap 74, as are the centertubesand liners associated with respective subassembly, as illustrated inFIG. 6. The assembly of both filter portions onto a substantially planarendcap reduces the cost and complexity of the parts, and simplifiesassembly. The endcap 74 also provides an annular groove 55 near itsouter periphery, which as has been described provides a mechanism bywhich a simple radial seal gasket 54 is fixed to the filter cartridge.As shown in FIG. 1, the gasket 54 has a simple depending skirt 76 and asmaller circumferential bead 77 which fits into the groove 55, providinga relatively simple and inexpensive but highly effective radial seal forthe filter cartridge. The gasket is sized to require stretching and apositive snap fit within the groove, making for a reliable and securebut simple gasket mount.

To seal the upper end of the filter, a third endcap is provided as shownin FIG. 7. An endcap 80 is joined at the top end of the filter to sealthe upper end of the filter element 21, and preferably also the liner 23and plastic centertube 22. The upper end of the bypass subassembly isalso secured by way of the upper endcap 80, which contacts the upperportion of the standoffs and fixes them in location. Sealing isaccomplished by potting as described above.

Conveniently, the upper endcap 80 has an annular groove 52 at its outerperiphery which supports a simple axial seal gasket 50. The groove 52 isformed not unlike the groove 55 of the lower endcap. However, the gasket50 can be a simple flat annular rubber member which has an insidediameter capable of fitting into the groove 52, and a outside diametercapable of fitting between the elements of the cover and base of thecanister. The gasket is sized so that it is stretch fit to positivelysnap into the groove 52, substantially eliminating the possibility ofinadvertently removing it. Using an axial seal gasket is advantageous,in that screwing the cover onto the canister serves to engage the gasketby compressing it only for a portion of the last turn of the cover, inthe tightening of the cover onto the housing.

Other features associated with the upper endcap 80 include a handle 58which provides a reliable means of removing the cartridge from thehousing when a filter change is desired. FIG. 3 illustrates a pluralityof small triangular projections 82 formed just below the gasket area 50help to center the upper portion of the cartridge as it is inserted intothe canister. In one embodiment projections are located at about 30°intervals around the circumference of the endcap. As shown in FIG. 3these projections 82 ride along ridge 82 b when the filter is insertedin the housing. The bottoms 82 a of the projections 82 seat on a ledge82 c of the housing to prevent the downward forces of the filter fromcrushing it into the housing. One or more radial holes 90 are alsoformed in the top endcap (see FIG. 1) in order to provide pressureequalization above the upper gasket 50. This is accomplished withoutproviding a leak path between the unfiltered and filtered oil whichflows through the filter.

The two seals on the cartridge, namely the radial seal 54 at the lowerend and the axial seal 50 at the upper end, are both simple and reliablyheld in place on the cartridge itself. Both are securely held in placeby the aforementioned annular grooves. There is no need for a mechanicto select a particular gasket or to see that a particular gasket is fitinto a proper position before attempting to install the filter. With thegaskets already installed as taught herein, and particularly includingthe simple nature of the gaskets, fitting of the cartridge is almost assimple as changing a spin-in cartridge. The gaskets are carried by thecartridge to their reliable position for installation, usually withoutfault.

Use of a radial seal as the lower gasket is worthy of note in that thegasket is positioned near the outer periphery of the filter, and thepressure differential serves to enhance the sealing action. The gasket54 seals radially between itself, the endcap 74 which supports it, andthe cartridge housing flange 46 (see FIG. 3). This seal separates thefiltered and unfiltered fluid. Use of a radial seal for this componentutilizes the pressure differential across the filter to assist thesealing function by forcing the radial seal gasket against both theendcap 74 which supports it and a cartridge housing flange 46 of thefilter housing.

The upper axial seal gasket is also note worthy in that it provides theability for easy removal and replacement of the housing cover. Aconventional radial seal gasket at the top would require the use of awrench and additional effort to remove the cover. The axial seal, whileit provides a reliable seal, releases as soon as the cover begins toturn, so that the cap can be easily removed for filter changes.

It will thus be seen that what has been provided is a new and innovativefilter cartridge constructed as a dual flow bypass filter, which isenvironmentally friendly, contains no metal parts, and is relativelysimple and inexpensive both to manufacture and to install.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein.- Allmethods described herein can be performed in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. An environmentally friendly dual lube filter cartridge containing no metal parts, and comprising in combination: a non metallic venturi centertube having a venturi throat and at least one venturi port, a bypass filter coaxial with the venturi centertube, and a first flow passage between the bypass filter and the venturi centertube for dual filtered fluid, a full flow filter having a non-metallic centertube and mounted coaxial with the bypass filter, the full flow centertube having a bore which is larger than the outer periphery of the bypass filter to create a second flow passage for single filtered fluid, a first plastic endcap sealing an end of the bypass filter to an end of the venturi centertube, the first endcap having standoffs for creating a flow path for single filtered fluid from the second flow passage to the venturi centertube, a second plastic endcap joining the full flow filter, the bypass filter and the venturi centertube, the second endcap having a central passage connected to the venturi centertube for flow of fluid from the cartridge, the second endcap also having an annular groove for receiving a skirt-like radial seal gasket positioned near the periphery of the full flow filter, and a third endcap enclosing the upper end of the cartridge and sealingly joined to the full flow filter element, the standoffs on the first endcap providing flow passages between the bypass element and the third endcap, the third endcap having an annular peripheral groove for carrying an axial seal gasket and including an annular disc-like axial seal gasket seated in the annular peripheral groove.
 2. The filter cartridge as in claim 1 further including a perforated liner on the full flow filter.
 3. The filter cartridge as in claim 2 wherein the liner has no perforations near the axial center of the filter.
 4. The filter cartridge as in claim 1 wherein the third endcap has centering protrusions.
 5. The filter cartridge as in claim 4 wherein the centering protrusions have shoulders at their lower ends.
 6. The filter cartridge as in claim 1 including a skirt-like annular radial seal gasket having a reduced diameter section sized to seat in the annular peripheral groove in the second endcap so that fluid pressure presses the seal into sealing relationship with the second endcap.
 7. The filter cartridge as in claim 6 wherein the radial seal gasket has a reduced diameter portion sized to be stretch fit and snapped into the annular peripheral groove for secure mounting.
 8. The filter cartridge as in claim 1 wherein the axial seal gasket is sized to positively snap into the annular peripheral groove for positive retention.
 9. The filter cartridge as in claim 1 wherein the third endcap further includes a handle for aiding manual manipulation of the cartridge.
 10. The filter cartridge as in claim 1 wherein the third endcap includes at least one pressure relieving port for equalizing pressure on opposite sides of the third endcap.
 11. An environmentally friendly dual lube filter cartridge containing no metal parts, and comprising in combination: a cylindrical bypass filter element mounted coaxially around a plastic venturi centertube, a cylindrical full flow filter element surrounding and concentric with the bypass filter, and providing a flow path between the full flow and bypass filters, and a maximum of three plastic endcaps sealing the ends of both said filter elements and including: a first substantially planar endcap sealing the first ends of both the full flow and bypass filter elements in a common plane, a second internal plastic endcap sealing a second end of the bypass filter and providing concentric standoffs within a bore of the full flow filter, a third plastic endcap sealing the second end of the full flow filter and the standoffs, whereby the standoffs provide a flow path between said flow path and the centertube, and the third endcap having a pressure relief aperture for limiting deflection of the plastic endcap caused by differential pressures in use.
 12. The filter cartridge as in claim 11 wherein the first endcap has an annular groove near the outer periphery thereof, and further including a skirt-type radial seal having a mounting bead snap fit into the annular groove.
 13. The filter cartridge as in claim 12 in which the third endcap has an annular groove at the outer periphery thereof, and further including a planar axial seal gasket snapped into the annular groove for retention, and providing an axial seal at the upper end of the filter cartridge.
 14. The filter cartridge as in claim 13 wherein the third endcap further includes centering protrusions for engaging an opening of a housing to center the cartridge, the protrusions having bases positioned to support the cartridge and the third plastic endcap from the housing to resist deformation of the plastic endcap under operating pressure.
 15. The filter cartridge as in claim 11 in which the third endcap has an annular groove at the outer periphery thereof, and further including a planar axial seal gasket snapped into the annular groove for retention, and providing an axial seal at the upper end of the filter cartridge.
 16. The filter cartridge as in claim 15 wherein the third endcap further includes centering protrusions for engaging an opening of a housing to center the cartridge, the protrusions having bases positioned to support the cartridge and the third plastic endcap from the housing to resist deformation of the plastic endcap under operating pressure.
 17. An environmentally friendly dual lube filter cartridge containing no metal parts, and comprising in combination: a non metallic venturi centertube having a venturi throat and at least one venturi port, a bypass filter coaxial with the venturi centertube, and a first flow passage between the bypass filter and the venturi centertube for dual filtered fluid, a full flow filter including a perforated liner on the full flow filter, having a non-metallic centertube, and mounted coaxial with the bypass filter, the full flow centertube having a bore which is larger than the outer periphery of the bypass filter to create a second flow passage for single filtered fluid, a first plastic endcap sealing an end of the bypass filter to an end of the venturi centertube, the first endcap having standoffs for creating a flow path for single filtered fluid from the second flow passage to the venturi centertube, a second plastic endcap joining the full flow filter, the bypass filter and the venturi centertube, the second endcap having a central passage connected to the venturi centertube for flow of fluid from the cartridge, the second endcap also having an annular groove for receiving a skirt-like radial seal gasket positioned near the periphery of the full flow filter, and a third endcap enclosing the upper end of the cartridge and sealingly joined to the full flow filter element, the standoffs on the first endcap providing flow passages between the bypass element and the third endcap, the third endcap having an annular peripheral groove for carrying an axial seal gasket.
 18. The filter cartridge as in claim 17 wherein the liner has no perforations near the axial center of the filter.
 19. The filter cartridge as in claim 17 wherein the third endcap has centering protrusions.
 20. The filter cartridge as in claim 19 wherein the centering protrusions have shoulders at their lower ends.
 21. The filter cartridge as in claim 17 including a skirt-like annular radial seal gasket having a reduced diameter section sized to seat in the annular peripheral groove in the second endcap so that fluid pressure presses the seal into sealing relationship with the second endcap.
 22. The filter cartridge as in claim 21 wherein the radial seal gasket has a reduced diameter portion sized to be stretch fit and snapped into the annular peripheral groove for secure mounting.
 23. The filter cartridge as in claim 17 wherein the third endcap further includes a handle for aiding manual manipulation of the cartridge.
 24. The filter cartridge as in claim 17 wherein the third endcap includes at least one pressure relieving port for equalizing pressure on opposite sides of the third endcap.
 25. An environmentally friendly dual lube filter cartridge containing no metal parts, and comprising in combination: a non metallic venturi centertube having a venturi throat and at least one venturi port, a bypass filter coaxial with the venturi centertube, and a first flow passage between the bypass filter and the venturi centertube for dual filtered fluid, a full flow filter having a non-metallic centertube and mounted coaxial with the bypass filter, the full flow centertube having a bore which is larger than the outer periphery of the bypass filter to create a second flow passage for single filtered fluid, a first plastic endcap sealing an end of the bypass filter to an end of the venturi centertube, the first endcap having standoffs for creating a flow path for single filtered fluid from the second flow passage to the venturi centertube, a second plastic endcap joining the full flow filter, the bypass filter and the venturi centertube, the second endcap having a central passage connected to the venturi centertube for flow of fluid from the cartridge, the second endcap also having an annular groove for receiving a skirt-like radial seal gasket positioned near the periphery of the full flow filter, and a third endcap enclosing the upper end of the cartridge and sealingly joined to the full flow filter element, the standoffs on the first endcap providing flow passages between the bypass element and the third endcap, the third endcap having an annular peripheral groove for carrying an axial seal gasket, and the third endcap including centering protrusions.
 26. The filter cartridge as in claim 25 wherein the centering protrusions have shoulders at their lower ends.
 27. The filter cartridge as in claim 25 including a skirt-like annular radial seal gasket having a reduced diameter section sized to seat in the annular peripheral groove in the second endcap so that fluid pressure presses the seal into sealing relationship with the second endcap.
 28. The filter cartridge as in claim 27 wherein the radial seal gasket has a reduced diameter portion sized to be stretch fit and snapped into the annular peripheral groove for secure mounting.
 29. The filter cartridge as in claim 25 wherein the third endcap further includes a handle for aiding manual manipulation of the cartridge.
 30. The filter cartridge as in claim 25 wherein the third endcap includes at least one pressure relieving port for equalizing pressure on opposite sides of the third endcap.
 31. An environmentally friendly dual lube filter cartridge containing no metal parts, and comprising in combination: a non metallic venturi centertube having a venturi throat and at least one venturi port, a bypass filter coaxial with the venturi centertube, and a first flow passage between the bypass filter and the venturi centertube for dual filtered fluid, a full flow filter having a non-metallic centertube and mounted coaxial with the bypass filter, the full flow centertube having a bore which is larger than the outer periphery of the bypass filter to create a second flow passage for single filtered fluid, a first plastic endcap sealing an end of the bypass filter to an end of the venturi centertube, the first endcap having standoffs for creating a flow path for single filtered fluid from the second flow passage to the venturi centertube, a second plastic endcap joining the full flow filter, the bypass filter and the venturi centertube, the second endcap having a central passage connected to the venturi centertube for flow of fluid from the cartridge, the second endcap also having an annular groove for receiving a skirt-like radial seal gasket positioned near the periphery of the full flow filter, the second endcap including a skirt-like annular radial seal gasket having a reduced diameter section sized to seat in the annular peripheral groove in the second endcap so that fluid pressure presses the seal into sealing relationship with the second endcap, and a third endcap enclosing the upper end of the cartridge and sealingly joined to the full flow filter element, the standoffs on the first endcap providing flow passages between the bypass element and the third endcap, the third endcap having an annular peripheral groove for carrying an axial seal gasket.
 32. The filter cartridge as in claim 31 wherein the radial seal gasket has a reduced diameter portion sized to be stretch fit and snapped into the annular peripheral groove for secure mounting.
 33. The filter cartridge as in claim 31 wherein the third endcap further includes a handle for aiding manual manipulation of the cartridge.
 34. The filter cartridge as in claim 31 wherein the third endcap includes at least one pressure relieving port for equalizing pressure on opposite sides of the third endcap.
 35. An environmentally friendly dual lube filter cartridge containing no metal parts, and comprising in combination: a non metallic venturi centertube having a venturi throat and at least one venturi port, a bypass filter coaxial with the venturi centertube, and a first flow passage between the bypass filter and the venturi centertube for dual filtered fluid, a full flow filter having a non-metallic centertube and mounted coaxial with the bypass filter, the full flow centertube having a bore which is larger than the outer periphery of the bypass filter to create a second flow passage for single filtered fluid, a first plastic endcap sealing an end of the bypass filter to an end of the venturi centertube, the first endcap having standoffs for creating a flow path for single filtered fluid from the second flow passage to the venturi centertube, a second plastic endcap joining the full flow filter, the bypass filter and the venturi centertube, the second endcap having a central passage connected to the venturi centertube for flow of fluid from the cartridge, the second endcap also having an annular groove for receiving a skirt-like radial seal gasket positioned near the periphery of the full flow filter, and a third endcap enclosing the upper end of the cartridge and sealingly joined to the full flow filter element, the standoffs on the first endcap providing flow passages between the bypass element and the third endcap, the third endcap having an annular peripheral groove for carrying an axial seal gasket, and the third endcap including at least one pressure relieving port for equalizing pressure on opposite sides of the third endcap.
 36. The filter cartridge as in claim 35 wherein the third endcap further includes a handle for aiding manual manipulation of the cartridge.
 37. The filter cartridge as in claim 1 wherein at least one of the full flow filter and bypass filter comprise a filter media including paper.
 38. The filter cartridge as in claim 1 wherein at least one of the full flow filter and bypass filter comprise a pleated filter media.
 39. The filter cartridge as in claim 1 wherein at least one of the full flow filter and bypass filter comprise a filter media including cellulose.
 40. The filter cartridge as in claim 1 wherein at least one of the full flow filter and bypass filter comprise a filter media including polyester. 